Magnetoresistive Sensors Based on Nanoparticles in Novel Silica Gels

The GMR-effect (giant magnetoresistance) can be observed in structures with alternating magnetic and non-magnetic layers measuring only a few nanometers, i.e. a few millionths of a millimeter. In 2007, Peter Grünberg and Albert Fert were awarded the Nobel Prize in Physics for its discovery.

In this project, the GMR-effect is to be explored for its use in sensor technology. The structures shall consist of magnetic carbon-coated cobalt nanoparticles in conductive silica gels. The nanoparticles can be synthesized with specific chemical and physical properties, enabling e.g. the binding of particles to be detected by the sensor. Novel silica gels will be developed that, e.g., keep their conductivity constant when transitioning from liquid to solid phase. Thus, the magnetic nanoparticles can be structured through external magnetic fields in liquid gels and keep their magnetic structures upon solidification of the gel. The experimental research will be supported by modelling and simulating the impact of the external magnetic fields and of the silica gel properties on the structuring process of the magnetic nanoparticles and the resulting GMR characteristics. Ultimately, this technology can be exploited for manufacturing printable nanoparticular sensors in a resource- and cost-efficient way.